Technological Field
The present invention relates to an image forming apparatus and an image forming program.
Description of the Related Art
An image forming apparatus includes an image forming unit, a transfer unit, and a fixing unit. The image forming unit includes a photosensitive drum on which an electrostatic latent image is formed, and forms a toner image on a paper sheet P as a recording medium, using an electrophotographic process. The transfer unit has an intermediate transfer belt onto which the toner image is transferred, and transfers the toner image onto the paper sheet conveyed thereto. The fixing unit fixes the toner image to the paper sheet.
Meanwhile, in a case where a difference is caused between the sheet conveyance velocity at the transfer unit and the sheet conveyance velocity at the fixing unit due to component tolerance, component wear, a temperature change, sheet rigidity, sheet length, or the like, a large conveyance reaction force is generated on the intermediate transfer belt. This is particularly conspicuous in a case where the paper sheet is thick paper. In such a case, the moving speed of the intermediate transfer belt is made to fluctuate, and color misregistration and density unevenness that will lead to an image defect are caused in the toner image.
To counter this, JP 2008-94573 A discloses a technology by which a section for detecting the angular velocity of the driving roller of an intermediate transfer belt is provided, and fluctuations in the moving speed of the driving roller are canceled by feedforward control based on the result of the detection.
However, fluctuations in the angular velocity of the driving roller of the intermediate transfer belt do not directly represent fluctuations in the moving speed of the intermediate transfer belt, and probably differ from the fluctuations in the moving speed of the intermediate transfer belt. Therefore, the effect to reduce fluctuations in the moving speed of the intermediate transfer belt is limited, and occurrences of color misregistration and density unevenness are not effectively reduced.